The Adafruit [RGB LCD Shield Kit](https://www.adafruit.com/products/714) is pretty cool in that it reduces your pins needed on the microcontroller to just 2 (6 are required on the LCD unit right?). As a last resort, what do you think of dropping the LCD display and incorporating an RGB LED like the Public Labs folk did with the [Thermal Flashlight](http://publiclaboratory.com/tool/thermal-photography)? In the interrupt routine a blinking green light would indicate it's ready for input of the phone number, a blinking red light would indicate it's ready for input for the upper bound, and a blinking blue light would indicate it's ready for input for the lower bound. When the unit is told to display the temperature, it would take the upper and lower bounds and display it somewhere between red-green-blue depending on where the current reading is in the upper and lower bounds. Am I missing anything else the LCD could be used for? The advantage here is that one RGB LED ([$1.95 at the high end](http://www.sparkfun.com/products/10820)) is cheaper than an LCD screen but the drawback is user friendliness. My "advantage" is definitely in the spirit of "How cheap can we get this?" but the cost/benefit analysis may not hold up on this suggestion.
Comments
Come to think of it, I think
Good catch. I didn't even
How about using an RGB LED instead of an LCD?
For those who aren't sure
For those who aren't sure